The bright stuff: we need Hirst more than some billionaire. Photograph: Getty

It seems destined to be bought by some foreign billionaire. Historical candidates might have been Lorenzo de' Medici or Catherine the Great. Modern ones - who knows?

Well, I have a modest proposal: Save the Diamond Skull for the Nation.

If ever there was a work of art that deserved a national campaign to keep it in this country, this is it. Raphael's Madonna of the Pinks could have hung equally beautifully in Washington DC or New York, without seriously depleting our superb public collections of Renaissance art.

Yet what masterpiece will remain in London to remind us of the best British artist of modern times? The Tate will have only a few shells and pill bottles as mementos of Hirst. For the Love of God - the diamond skull - is the perfect Hirst for a museum. Unlike the shark, which decayed, it is almost totally imperishable. It is designed to be a rock for the ages, covered in rocks. It's a wonder of the modern world, with all the darkness at its hollow centre that implies. It is, in its rarity and eerie beauty, one of the most amazing artefacts ever made in this country.

Hirst is a British treasure and the skull is his masterpiece, so start raising the money, all you worthies, you art funds.

Once, our public collections would have leaped at something like this. In the 1890s the British Museum bought a crystal skull, believed to be pre-Conquest American, from Tiffany's: it is now dismissed as a fake but the amazing thing is that our museums were once competitors in such a market. It would be such a great way to say that we really believe in our museums, as well as our art, to buy the skull and put it in a public collection.

But which collection? The skull would make as much sense in the geological galleries of the Natural History Museum as in Tate Modern. It would look as telling in the V&A as in the British Museum. That it could grace so many collections, can be seen in so many ways, is a measure of it.

Personally I'd like to see it in Bloomsbury, near the funeral treasure of Sutton Hoo - so we can see how exactly how far we have come.